If the shoe fits, wear it. If not, Zappos.com will gladly take it back at no cost to you. Zappos.com has become the #1 seller of shoes online (ahead of J.C. Penney) by stressing customer service. It stocks 3 million pairs of shoes, handbags, and apparel and accessories, specializing in some 1,000 brands that are difficult to find in mainstream shopping malls.